Structures for cross-talk reduction

ABSTRACT

Systems and apparatuses for electromagnetic communications are provided. One of the apparatuses includes a housing portion for an electronic device, wherein the housing portion comprises: a first region formed from a first material; and a second region comprising an arrangement of structures formed from the first material and a second material, wherein the arrangement of structures reduce propagation of electromagnetic radiation propagating through the second region.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit of priorityto U.S. patent application Ser. No. 15/398,588, filed on Jan. 4, 2017,the contents of which are hereby incorporated by reference.

BACKGROUND

This specification relates to electromagnetic communications. Advancesin semiconductor manufacturing and circuit design technologies haveenabled the development and production of integrated circuits (ICs) withincreasingly higher operational frequencies. In turn, electronicproducts and systems incorporating high frequency integrated circuitsare able to provide greater functionality than previous generations ofproducts. The additional functionality has typically included theprocessing of increasingly larger amounts of data at increasingly higherspeeds.

Many conventional electronic systems include multiple printed circuitboards (PCBs) upon which ICs are mounted, and through which varioussignals are routed to and from the ICs. Connecting to PCBs byconventional means, e.g., signal-carrying mechanical connectors,generally creates discontinuities, requiring expensive electronics tonegotiate. Conventional mechanical connectors may also wear out overtime, require precise alignment and manufacturing methods, and aresusceptible to mechanical jostling.

Communication channels can be formed between one or more transmitterintegrated circuit package of one device and one or more correspondingreceiver integrated circuit package of another device. Communicationsignals of a particular communication channel intended for a particularreceiver integrated circuit can leak to one or more other communicationchannels, resulting in cross-talk interference.

SUMMARY

The devices and methods disclosed herein allow for reduced cross-talkbetween communication channels. A communication channel can be formedbetween a transmitter integrated circuit package of one device and areceiver integrated circuit package of another device. Transmitterintegrated circuit packages and receiver integrated circuit packages canalso be referred to as connectors. Cross-talk can occur internallywithin a single device when signals intended for transmission outsidethe device is received by the receiver of the device.

The devices and methods disclosed herein can reduce a material volume ofthe devices compared to systems that use distance or absorber structuresto isolate the devices and/or individual communication channels. A widerange of materials can be selected to be incorporated into the devicesto reduce cross-talk, allowing flexible implementation of the methodsand devices disclosed herein, simplifying their fabrication. Someexamples of materials that can be chosen include plastics, zirconia, andother insulating materials. For example, structures can be implantedwithin housing/cases of devices.

In general, one innovative aspect of the subject matter described inthis specification can be embodied in apparatuses that include a housingportion for an electronic device, wherein the housing portion includes:a first region formed from a first material; and a second regionincluding an arrangement of structures formed from the first materialand a second material, wherein the arrangement of structures reducepropagation of electromagnetic radiation propagating through the secondregion.

The foregoing and other embodiments can each optionally include one ormore of the following features, alone or in combination. In particular,one embodiment includes all the following features in combination. Thearrangement of structures includes a periodic arrangement of the firstmaterial and the second material. The housing portion of the housingincluding the arrangement of structures has a planar exterior surface.The housing portion is configured to be placed over a first connector,the first region is vertically above the first connector, the firstconnector is configured to transmit electromagnetic radiation throughthe first region, and the arrangement of the structures comprisesmultiple concentric circles surrounding the first region. The housingportion is configured to be placed over multiple connectors, themultiple connectors are configured to transmit electromagnetic radiationthrough the first portion, and the arrangement of the structures isdisposed in regions of the housing portion that are above gaps betweenthe multiple connectors. Multiple holes, slots, or trenches are definedin the first material of the top portion of the housing, and the secondmaterial fills the multiple holes to form the arrangement of structures.Multiple slots are defined in the first material, the top portion has afirst width and a first length, and the multiple slots extend across thewidth of the housing portion. A width of the slot filled with the secondmaterial is a quarter of a wavelength of the electromagnetic radiationin the second material, and a dimension of a distance between slots inthe multiple slots is a quarter of a wavelength of the electromagneticradiation in the first material. The arrangement of structures isconfigured to filter electromagnetic radiation having a wavelengthbetween 50 GHz to 70 GHz. A bandwidth of the filter is less than 60%.Multiple holes, slots, or trenches filled with the second material areformed integrally with the housing portion by injection molding. Thefirst material includes plastic and the second material includes foam.The electromagnetic radiation is between 50 to 70 GHz and thearrangement of structures reduces a transmission between a first end ofthe second region and a second end of the second region by more than 40%over a bandwidth of 5 GHz. The arrangement of structures formed from thefirst material and the second material includes multiple structureshaving one or more different shapes and/or one or more differentdistances between the multiple structures. The arrangement of thestructures includes multiple structures having different heights. Thearrangement of structures includes structures that have heights smallerthan a thickness of the housing.

In general, one innovative aspect of the subject matter described inthis specification can be embodied in communications modules thatinclude a transmitter integrated circuit package, a receiver integratedcircuit package; a housing enclosing the transmitter integrated circuitpackage and the receiver integrated circuit package, wherein the housingincludes a first material that permits electromagnetic radiation to betransmitted from the transmitter integrated circuit package enclosed bythe housing through the housing; and multiple structures formed of asecond material different from the first material defined in a region ofthe housing configured to reduce propagation of electromagnetic signalswithin the housing, wherein the structures are positioned in the regionsuch that a propagation path through the housing of an electromagneticsignal from the transmitter integrated circuit package to the receiverintegrated circuit package crosses one or more of the multiplestructures.

The foregoing and other embodiments can each optionally include one ormore of the following features, alone or in combination. Thecommunication module further includes an absorber structure, and aprinted circuit board on which the transmitter integrated circuitpackage and the receiver integrated circuit package are mounted, whereinthe multiple structures formed of the second material are configured toreduce cross-talk between the transmitter integrated circuit package andthe receiver integrated circuit package. The communication module isconfigured to establish a communication channel when a secondcommunication module is placed in proximity to the communication module,and wherein the communication channel is between a transmitterintegrated circuit package of the second communication module and thereceiver integrated circuit package of the communication module, orbetween a receiver integrated circuit package of the secondcommunication module and the transmitter integrated circuit package ofthe communication module. The multiple structures formed of a secondmaterial include a periodic arrangement of the first material and thesecond material. Multiple holes, slots, or trenches are defined in thefirst material of the housing, and the second material fills themultiple holes to form the arrangement of structures. The housingincluding the multiple structures has a planar exterior surface.Multiple slots are defined in a portion of the housing, the housinghaving a first width and a first length, and the multiple slots extendacross the width of the housing. A width of the slot filled with thesecond material is a quarter of a wavelength of the electromagneticradiation in the second material, and a dimension of a distance betweenslots in the multiple slots is a quarter of a wavelength of theelectromagnetic radiation in the first material. The multiple structuresare configured to filter electromagnetic radiation having a wavelengthbetween 50 GHz to 70 GHz.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an overhead view of an example IC package.

FIG. 2 shows a side view representation of an example communicationdevice including an IC package.

FIG. 3 is a side view of an example communication module including asignal guiding structure.

FIG. 4 is a side view diagram illustrating an example of communicationbetween a transmitter and a receiver.

FIG. 5A shows a side view diagram illustrating an example ofcommunication between a pair of communication modules.

FIG. 5B shows a model system that includes a pair of communicationmodules.

FIG. 6 shows a side view diagram illustrating an example ofcommunication between a pair of communication modules.

FIG. 7A shows a schematic diagram of a series of structures between twocommunication modules.

FIG. 7B shows a plot of a bandwidth of a filter as a function ofrelative permittivity.

FIG. 7C shows a side view diagram illustrating a pair of communicationmodules including a signal blocking structure.

FIG. 7D shows a model system that includes a series of structuresbetween two communication modules.

FIG. 7E shows plots of reflection coefficient and transmissioncoefficient for the model system shown in FIG. 7D as a function offrequency.

FIG. 8 shows a side view diagram illustrating a pair of communicationmodules including a signal blocking structure.

FIG. 9 shows a top view of a device housing incorporating a series ofstructures.

FIG. 10A shows a side view diagram of a communication moduleincorporating a series of structures.

FIG. 10B shows a top view of a communication module incorporating aseries of structures.

FIG. 10C shows reflection coefficient plots for different systems.

FIG. 10D shows a side view diagram of a communication moduleincorporating a series of structures.

FIG. 10E shows a top view of a communication module incorporating aseries of structures.

FIG. 11A shows a top view diagram of a series of structures.

FIG. 11B shows a side view diagram of an arrangement of structures.

FIG. 11C shows a side view diagram of an arrangement of structures.

FIG. 11D shows a side view diagram of a series of structures.

FIG. 11E shows a side view diagram of a series of structures.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

This specification describes electromagnetic (EM) blocking structuresfor contactless communication. In particular, this specificationdescribes the use of signal blocking structures that introducediscontinuities to reduce cross-talk between communication channels.

Contactless communication may be used to provide signal communicationsbetween components on a device or may provide communication betweendevices. In one example, tightly-coupled transmitter/receiver pairs maybe deployed with a transmitter disposed at a terminal portion of a firstconduction path and a receiver disposed at a terminal portion of asecond conduction path. The transmitter and receiver may be disposed inclose proximity to each other depending on the strength of thetransmitted energy, and the first conduction path and the secondconduction path may not be contiguous with respect to each other. Insome examples, the transmitter and receiver may be disposed on separatecircuit carriers positioned with the antennas of thetransmitter/receiver pair in close proximity. This specificationdescribes a number of different structures that can be employed toreduce or block stray signals leaking from a transmitter associated witha first communication channel to a receiver of another communicationchannel.

Contactless communication A transmitter and/or receiver may beconfigured as an integrated circuit (IC) package, in which one or moreantennas may be positioned adjacent to a die and held in place by adielectric or insulating encapsulation or bond material. An antenna mayalso be held in place by a lead frame substrate. Examples of antennasembedded in IC packages are shown in the drawings and described below.Note that IC packages may also be referred to as simply packages, andare examples of contactless communication units that are also variouslyreferred to as communication units, communication devices, comm-linkchips, comm-link chip assemblies, comm-link chip packages, and/orcomm-link packages, which may be configured in various ways. Forexample, IC packages, communication units, communication devices,comm-link chips, comm-link chip assemblies, comm-link chip packages,and/or comm-link packages may each include one or more ICs, chips, ordies and have circuit functionality appropriate for particularapplications.

FIG. 1 shows an example IC package 100. The IC package 100 includes adie 102 and a transducer 104 providing conversion between electrical andelectromagnetic (EM) signals. The IC package 100 may include additionalstructures, for example, conductive connectors, such as bond wires,electrically connecting the transducer to bond pads connected to atransmitter or receiver circuit included in die 102. The IC package 100further includes an encapsulating material 106 formed around at least aportion of the die 102 and/or the transducer 104. In the example ICpackage 100, the encapsulating material 104 completely covers the die100 and the transducer 104.

The die 102 includes any suitable structure configured as a circuit on asuitable die substrate. In some implementations, the die canalternatively be referred to as a chip or an integrated circuit. The diesubstrate may be composed of any suitable semiconductor material, forexample, silicon. In some implementations, the die 102 has a length anda width dimension each of substantially 1.0 mm to about 2.0 mm. The die102 may be mounted with electrical conductors, such as a lead frame, notshown in FIG. 1, electrically coupling the die 102 to one or moreexternal circuits. The IC package 100 can further include a transformerto provide impedance matching between a circuit on the die 102 and thetransducer 104.

The transducer 104 may be in the form of a folded dipole, patch antenna,bow tie antenna, loop antenna, or other types of antennas, and isconfigured to transmit and/or receive electromagnetic signals. In someimplementations, the antenna is configured to operate at radiofrequencies including radio frequencies in the extremely high frequency(EHF) band of the electromagnetic spectrum, e.g., frequencies from 30 to300 gigahertz. As shown in IC package 100, the antenna is separate fromthe die 102, but is coupled to the die 102 by suitable conductors, notshown.

The dimensions of the antenna are determined such that they are suitablefor operation in the specified frequency band of the electromagneticspectrum, e.g., the EHF band.

In one example, a loop configuration of the antenna can be configured toinclude a substantially 0.1 mm band of material, laid out in a loopsubstantially 1.4 mm long and substantially 0.53 mm wide, with a gap ofsubstantially 0.1 mm at the mouth of the loop, and with the edge of theloop approximately 0.2 mm from the edge of die 102.

The encapsulating material 106 can be used to assist in holding thevarious components of IC package 100 in fixed relative positions. Theencapsulating material 106 may be formed from a suitable materialconfigured to provide electrical insulation and physical protection forthe components of IC package 100. Additionally, the encapsulatingmaterial 106 can be selected from a material that does not impede, orthat optimizes passage of, signals to or from the transducer 104. Forexample, the encapsulating material 106 can be composed of glass,plastic, or ceramic. The encapsulating material 106 may also be formedin any suitable shape. For example, the encapsulating material 106 maybe in the form of a rectangular block, encapsulating all components ofthe IC package 100 except for any unconnected ends of conductorsconnecting the die 102 to external circuits.

FIG. 2 shows a side view representation of an example communicationdevice 200 including an IC package 202 mounted to a PCB 204. The ICpackage 202 includes a die 206, a ground plane 208, an antenna 210, andone or more bond wires 212 connecting the die 206 to the antenna 210.The die 206 and antenna 210 are mounted on a package substrate 214 andencapsulated in an encapsulating material. The ground plane 208 iswithin the package substrate 214 and is a suitable structure configuredto provide an electrical ground for the antenna 210. The ground plane208 can extend the entire length of the package substrate 214 or just aportion, in particular, a portion underneath the antenna 210. The PCB204 includes a top dielectric layer 216 having a surface 218. The ICpackage 202 is mounted to the surface 218 with mounting bumps 220attached to a metallization pattern (not shown).

The PCB 204 also optionally includes a layer 222 spaced from dielectriclayer 216 made of conductive material forming a ground plane within thePCB 204. The PCB ground plane may be any suitable structure configuredto provide an electrical ground to circuits and components on the PCB204.

FIG. 3 is a side view of an example communication module 300 including asignal guiding structure. As shown in FIG. 3, the communication module300 includes a PCB 302, an IC package 304, and a signal guidingstructure 306 providing a signal pathway. The communication module 300,can include a transmitter or receiver for transmitting or receivingsignals, e.g., radio frequency signals.

In particular, the IC package 304 can correspond to the IC packagesdescribed above with respect to FIGS. 1 and 2. The IC package 304 ismounted on the PCB 302. For example, the IC package 304 can be mountedto the PCB as described with respect to FIG. 2.

The communication module 300 can be configured to transmit or receivedata using radio frequency communication. For example, if thecommunication module 300 includes a transmitter, the communicationmodule 300 can transmit data, which can then be received by a receiver,e.g., of another communication module.

The signal guiding structure 306 is configured to aid in directing radiofrequency (RF) signals as well as to reduce interference from signals.The signal guiding structure 306 can surround a perimeter of the ICpackage and extend in the direction of signal transmission and/orreception by a specified amount to provide a channel for emitted orreceived RF signals. For example, the signal guiding structure 306 canhave a height 310 suitable for a particular device including thecommunication module 300 and that allows the signal guiding structure306 to be positioned in proximity to a corresponding signal guidingstructure of another communication module when used to communicate withanother device. The signal guiding structure can be composed of asuitable material that is configured to reduce extraneous signalswithout disrupting passage of communications along the channel formed bythe signal guiding structure 306.

FIG. 3 illustrates one IC package 304 mounted to the PCB 302. However,in other implementations, more than one IC package can be mounted to thesame PCB 302.

The communication module 300 can be part of a communication system of adevice, e.g., a computer, mobile phone, tablet, kiosk, or otherdevice/system. The communication system can be configured to providecontactless communication using one or more IC packages. For example,the communication system can include two IC packages, one configured asa transmitter and the other configured as a receiver. The communicationsystem can be in communication with a storage device. Thus, for example,the communication system can transfer data between the data storage unitand an external device using contactless communication provided by theIC packages.

FIG. 4 is a side view diagram 400 illustrating an example ofcommunication between a transmitter and a receiver. For example, a userof a first device may wish to exchange data with a second device. Thetwo devices can be positioned in proximity to each other such that therespective communication modules for transmitting and receiving data arealigned and in range of each other. In particular, for EHF frequencies,the transmitter and receiver of the two devices may need to be withinspecified distances. The distances can vary, for example, depending onthe particular frequencies used, the materials between the transmitterand receiver, and the strength of the transmission.

In FIG. 4, a first device includes a first communication module having atransmitter IC package 402 positioned on a first PCB 404. Thetransmitter IC package 402 is surrounded by a first signal guidingstructure 406 forming a channel. The first signal guiding structure 406extends to a surface of a first housing 408 of the first device. Forexample, the first device can be a first mobile phone and the firsthousing 408 can correspond to the outer case of the first mobile phone.

A second device includes a second communication module having a receiverIC package 410 positioned on a second PCB 412. The receiver IC package410 is surrounded by a second signal guiding structure 414 forming achannel. The second signal guiding structure 414 extends to a surface ofa second housing 416 of the second device. For example, the seconddevice can be a second mobile phone and the second housing 416 cancorrespond to the outer case of the second mobile phone.

As illustrated by diagram 400, the first signal guiding structure 406and the second signal guiding structure 414 are aligned and an outersurface of the first housing 408 and the second housing 416 are inphysical contact to provide optimal communication distance andinterference.

A data transmission from the transmitter IC package 402 passes throughthe channel formed by the first signal guiding structure 406 and thesecond signal guiding structure 414 to the receiver IC package 410. Forexample, a pair of devices can communicate data between each other bytransmitting data from the transmitter IC package 402 to the receiver ICpackage 410. The signal guiding structures along with a proper alignmentcan maximize the power of the transmission that is received by thereceiver IC package. In some implementations, the signal guidingstructures can be formed from, or include a layer of, a metallicmaterial that reflects the transmitted data along the signal guidingstructures toward the receiver. In some other implementations, thesignal guiding structures can be formed from, or include a layer of, anelectromagnetic absorbing material to reduce stray signals that maycause interference.

Although transmitted signals from a transmitter are intended for receiptby a particular receiver, cross talk caused by leaking of signal toanother channel can result in unintended coupling that interferes withcommunication on that other channel. Example sources of cross-talk areillustrated in FIGS. 5A and 6.

Sources of Cross-Talk

FIG. 5A shows a side view diagram 500 illustrating an example ofcommunication between a pair of communication modules. Diagram 500includes a portion of a first device 502 and a second device 504.

The first device 502 includes a first communication module 501. Thefirst communication module 501 includes a first transmitter IC package506 and a first receiver IC package 508 mounted to a first PCB 510. Inthe example shown, each of the first transmitter IC package 506 and thefirst receiver IC package 508 is encircled by a respective first signalguiding structure 512, 513. The first signal guiding structures 512, 513each form a channel extending from the respective IC package to asurface of a first housing 514 of the first device 502. For example, thefirst device 502 can be a first mobile phone and the first housing 514can correspond to the outer case of the first mobile phone.Alternatively, the first device 502 can be a docking station and thefirst housing 514 can be the outer housing of the docking station.

As described above, the signal guiding structures can maximize the powerof the transmission that is received by the receiver IC package as wellas reduce signal leakage. In some alternative implementations, thedistance between the IC package and the housing surface is small and afully encircling signal guiding structure may be unnecessary. Instead,for example, an absorber structure can be positioned between thetransmitter and receiver IC packages.

The second device 504 includes a second communication module 503. Thesecond communication module 503 includes a second transmitter IC package516 and a second receiver IC package 518 mounted to a second PCB 520.Each of the second transmitter IC package 516 and the second receiver ICpackage 518 is encircled by a respective second signal guiding structure522, 523. The second signal guiding structures 522, 523 each provide achannel extending from the respective IC package to a surface of asecond housing 524 of the second device 502. For example, the seconddevice 502 can be a second mobile phone and the second housing 524 cancorrespond to the outer case of the second mobile phone. The seconddevice 504 can be a laptop and the second housing 524 can be the outercase of the laptop.

As shown in FIG. 5A, the first signal guiding structures 512, 513 andthe second signal guiding structures 522, 523 are substantially alignedon either side of the respective first and second housings 514, 524. Thealignment can assist in decreasing loss from a data transmission 526from the first transmitter IC package 506 to the second receiver ICpackage 518 and a data transmission 528 from the second transmitter ICpackage 516 to the first receiver IC package 508.

As described above, each signal guiding structure is configured to aidin directing radio frequency (RF) signals as well as to reduceinterference from signals. The signal guiding structure can at leastpartially surround a perimeter of the IC package and extend in thedirection of signal transmission and/or reception by a specified“height” amount to provide a channel for emitted or received RF signals.The signal guiding structure can be composed of a suitable material thatis configured to reduce extraneous signals without disrupting passage ofcommunications along the channel formed by the signal guiding structure.The guiding structure may be in part dielectric, conductive and/orabsorbing material. Lensing type structures can be built as part of aninterior surface of the case. Even with the signal guiding structures,the potential for unintended coupling between channels can occur.Unintended coupling can occur when signals transmitted by a transmitterIC package are received by unintended receivers. Due to the nature ofthe electromagnetic field generated by the transmitted signals,particularly at certain frequencies, some signals emitted from the firsttransmitter IC package 506 and intended for the second receiver ICpackage 518 can propagate to an adjacent channel, for example, the firstreceiver IC package 508.

Transmitter IC package and receiver IC package pairs form contactlessconnectors between the first device 502 and the second device 504. Thecontactless connectors are covered by the device housing (i.e., firsthousing 514 and second housing 524). The device housing can be devicecases that are made of plastic.

For example, as shown in FIG. 5A, the signal guiding structures 512 and513 extend to the housing 514 of the first device 502. The respectivehousings have a thickness that results in a gap having a thickness thatis the sum of the thicknesses of the first housing and the secondhousing between the corresponding signal guiding structures along thetransmission path. Additionally, the housing may be formed of a materialthat facilitates propagation of EM signals, e.g., a dielectric material.In addition, the dielectric material of the housing can serve as awaveguide for the signal. As a result, signals can propagate through thefirst housing 514 and/or the second housing 524, bypassing the signalguiding structures 512, 513, as illustrated by dashed line 530. Thesignals can then be received by the first receiver IC package 508. Thiscan lead to parasitic signals caused by interference, which are alsoknown as cross-talk between connector lanes. One connector lane can be,for example, the transmission of signal 526 from the transmitter ICpackage 506 of the first device 502 to receiver IC package 518 of thesecond device 504. A second connector lane can be, for example, thetransmission of signal 528 from the transmitter IC package 516 of thesecond device 504 to receiver IC package 508 of the first device 502.The cross-talk provided by signal leakage through the device housingsand PCB can cause coupling between the first transmitter IC package 506to the first receiver IC package 508.

Additionally, signals can propagate through the first PCB 510 where thesignals can be received by the first receiver IC package 508, asillustrated by dashed line 532.

FIG. 5B shows an example model system 540 having a first transmitter ICpackage 542 and a first receiver IC package 544 in the same device. Forexample, FIG. 5B can represent at test structure designed to illustratesignal propagation. A portion of a housing 546 laterally separates thefirst transmitter IC package 542 from the first receiver IC package 644.In comparison to the first device 502 shown in FIG. 5A, the model 540simplifies the system by not introducing a vertical displacement in thez direction between the receiver IC package/transmitter IC package andthe housing 546, which corresponds to the housing 514 in FIG. 5A.

Examples of system parameters used in the computation of the reflectionand transmission coefficients plots can include: a distance 548 betweenthe receiver IC package 544 and the transmitter IC package 542, a depth552 of the housing 546, a thickness 550 of the housing 546, thepermittivity of the material (e.g., plastic) of the housing 546 and aloss tangent measured internally at 60 GHz. The loss tangent quantifiesdielectric loss of a dielectric material's inherent dissipation ofelectromagnetic energy, for example, by heat. The values used herereflect that of an exemplary embodiment.

Besides parasitic propagation of signals internally within a device,FIG. 6 shows a side view diagram 600 illustrating a second example ofcommunication between a pair of communication modules, in which signalsfrom a transmitter of a first device are received by a receiver in anadjacent channel of a second device.

Diagram 600 includes a portion of a first device 602 and a second device604. The first device 602 includes a first communication module 601. Thefirst communication module 601 includes a first transmitter IC package606 and a second transmitter IC package 608 mounted to a first PCB 610.Each of the first transmitter IC package 606 and the second transmitterIC package 608 is at least partially encircled by a respective firstsignal guiding structure 612, 613 similar to the signal guidingstructures described above. The first signal guiding structures 612, 613each form a channel extending from the respective IC package to asurface of a first housing 614 of the first device 602. For example, thefirst device 602 can be a first mobile phone and the first housing 614can correspond to the outer case of the first mobile phone. The firstdevice 602 can also be a docking station and the first housing 614 cancorrespond to an external casing of the docking station.

The second device 604 includes a second communication module 603. Thesecond communication module 603 includes a first receiver IC package 616and a second receiver IC package 618 mounted to a second PCB 620. Eachof the first receiver IC package 616 and the second receiver IC package618 is at least partially encircled by a respective second signalguiding structure 622, 623. The second signal guiding structures 622,623 each provide a channel extending from the respective IC package to asurface of a second housing 624 of the second device 602. For example,the second device 602 can be a second mobile phone and the secondhousing 624 can correspond to the outer case of the second mobile phone.The second device 602 can also be a laptop and the second housing 624can be the housing of the laptop.

Unintended coupling of signals can also occur between communicationmodules. In particular, while signals transmitted by the firsttransmitter IC package 606 are intended for receipt by the firstreceiver IC package 616, some signals emitted from the first transmitterIC package 606 may be received by the second receiver IC package 618 ofthe second device 604. In particular, signals can propagate through thefirst housing 614 and/or the second housing 624, bypassing the firstsignal guiding structures 612, 613 and second signal guiding structures622, 623. Once again, the housing (614 and/or 624) can serve as awaveguide for the signals emitted from transmitter IC package 606, asshown by a dotted line 630. As a result, the cross-talk provided bysignal leakage through the device housings can cause unintended couplingbetween the first transmitter IC package 606 of the first device 602with the second receiver IC package 616 of the second device 604.

Structures for Reducing Cross-Talk

The example shown in FIGS. 5B and 5C can be considered a baseline ofsignal leakage. The following figures describe the use of additionalstructures that can reduce this level of signal leakage to provideimproved data communication.

FIG. 7A shows a schematic diagram of structures 742 that reduce or blockthe parasitic signals from propagating between a first portion 744 of ahousing 740 to a second portion 746 of the housing 740, after a signal748 is incident (e.g., normally, as shown in FIG. 7A, or obliquely (notshown)) on the first portion 744. The structures 742 are formed from aseries of alternating first material 750 and second material 752. Thefirst material 750 may be the same material as the housing 740, and thesecond material 752 is a different material from the first material 750.The first material 760 of the structures 742 can have a width d₁ and thesecond material 752 of the structures 742 can have a width d₂. The totalwidth of one unit of the first material 750 and the second material 752is a. The structures 742 can be a periodic structure of repeating units754, each having a width a. In other words, the first material 750within structures 742 can have a uniform width of d₁ and the secondmaterial 752 within structures 742 can have a uniform width of d₂.Alternatively, the arrangement of the structures can be non-periodic(i.e., the widths of either the first material or the second materialmay deviate within one or more portions of the structures 742.) When thestructures are not fully periodic, they generally broaden the effectivefrequency range at the expense of reducing the magnitude of the effect.

Perturbing the housing 740, which is formed of a first material (e.g.,plastic), by replacing selected portions of the housing 740 with asecond material having a different permittivity (e.g., alumina) preventsor reduces the propagation of the signal 748 inside the housing 740. Inother words, the second material (and the intervening first material)can act as a filter. The second material in the selected portions of thehousing can be arranged in a periodic fashion. The second material canbe formed in shapes such as circular, rod-shaped, or the second materialcan be formed in trenches or groves defined within the first material.

The signal 748 transmitted through the structures 742 to the secondportion 746 of the housing 740 can be compared with the signal 748propagating in the first portion 744 of the housing. The structures 742act as filters when they reduce or block the signal 748 from beingtransmitted to the second portion 746. FIG. 7B shows a plot 756 of thefilter bandwidth (in percent) as a function of the permittivity of thesecond material 752.

The width d₁ of the first material 750 can be a quarter of a wavelengthof the signal 748 in the first material. The wavelength of the signal inthe material is the free-space wavelength divided by the dielectricconstant (or permittivity) of the material. Because the material of thefirst material 750 (and of the housing 740) is about 2.35, the plot 756shows a dip to 0% filter bandwidth when the second material 752 also hasa permittivity of 2.35. Such a situation is equivalent to a continuouspiece of housing 740 that is made of a single uniform material, in whichcase, no filtering effect is provided. Instead, the housing 740 canadditionally act as a dielectric waveguide to guide the signal 748 fromthe first portion 744 to the second portion 746, resulting in a filterbandwidth of 0%.

Material can be removed from the housing 740 such that the structuresare formed with a second material 752 that is simply air. Air has arelative permittivity (ε_(r)), or dielectric constant, of 1, and thestructures 742 in this case provide a filter having a bandwidth of 28%.Plot 756 is independent of frequency. Since the bandwidth is plotted asa % of the signal frequency, it is what is called a normalized quantity.For example, if the transmitted frequency is 50 GHz, choosing a materialwith a dielectric constant of 5 would yield a bandwidth of 0.25×50 GHZ,or about 12.5 GHz. The effect of the periodic structure ismultiplicative, the shape of the bandpass multiplied by the originalbandpass. The structures are designed to be a band-stop filter forblocking a range of frequencies. As the dielectric constant of thesecond material 752 increases from 1 to match that of the first material750 (2.35), the filter bandwidth decreases. When the permittivity of thesecond material 752 increases above 2.35, the filter bandwidth increasesagain. Alumina has a high dielectric constant of between 9.3-11.5, andthe filter bandwidth is above 42% over that range. The plot 756 showsthat cross-talk between the transmitter IC package 706 and a receiver ICpackage 708 can be reduced (e.g., significantly attenuated) when aseries of structures are introduced into the housing. The filteringeffect accumulate for a number of structures in the series, and thisaffects the depth of the filter response. One element might block 50% (3dB) of the unwanted propagating signal. Two would block approximately 6dB (0.5*0.5). The effect is cumulative but, because the signal is alsospreading, not exactly multiplicative.

FIG. 7C shows a side view diagram 700 illustrating a pair ofcommunication modules including structures for reducing or blockingparasitic signal transmission between or within the communicationmodules.

Diagram 700 includes a portion of a first device 702 and a second device704. The first device 702 includes a first communication module 701. Thefirst communication module 701 includes a first transceiver IC package706 and a second transceiver IC package 708 mounted to a first PCB 710.Each of the first transceiver IC package 706 and the second transceiverIC package 708 is at least partially encircled by a respective firstsignal guiding structure 712, 713 similar to the signal guidingstructures described above.

The first signal guiding structures 712, 713 each form a channelextending from the respective transceiver IC package to a surface of afirst housing 714 of the first device 702. For example, the first device702 can be a first mobile phone and the first housing 714 can correspondto the outer case of the first mobile phone. Only a top portion of thefirst housing 714 is shown in FIG. 7C. The top portion is supported by arim portion (not shown). In some embodiments, the first signal guidingstructures 712 can serve as part of the rim portion used to support thetop portion of the first housing. Alternatively, a different rim portionis used to provide mechanical structural support to the top portion ofthe housing 714.

The first device 702 further includes structures 731. Structures 731 aresimilar to those shown in FIG. 7A. The structures 731 are spatiallypositioned adjacent to first housing 714 and between the channels formedby the first signal guiding structures 712 and 713. The structures 731are formed within the first housing 714. The structures 731 can beembedded within the first housing. Even though FIG. 7C shows thestructures 731 extending through the entire thickness of the firsthousing 714, the structures 731 can extend vertically only partiallythrough a portion of the thickness of the first housing 714 (e.g., halfthe thickness of the first housing 714, a quarter of the thickness ofthe first housing). In some other implementations, the spatial positionof the structures 731 can be any suitable position within theelectromagnetic field generated by signals leaking from the firsttransceiver IC package 706 toward the second transceiver package 708.

The second device 704 includes a second communication module 703. Thesecond communication module 703 includes a third transceiver IC package716 and a fourth transceiver IC package 718 mounted to a second PCB 720.Each of the third transceiver IC package 716 and the fourth transceiverIC package 718 is at least partially encircled by a respective secondsignal guiding structure 722, 723. The second signal guiding structures722, 723 each provide a channel extending from the respectivetransceiver IC package to a surface of a second housing 724 of thesecond device 704. For example, the second device 704 can be a secondmobile phone and the second housing 724 can correspond to the outer caseof the second mobile phone. Alternatively, the second device 704 can bea laptop, and the first device 702 can be a docking station. Only a topportion of the first housing 724 is shown in FIG. 7C. The top portion issupported by a rim portion (not shown). In some embodiments, the secondsignal guiding structures 722 and 723 can serve as part of the rimportion used to support the top portion of the first housing.Alternatively, a different rim portion is used to provide mechanicalstructural support to the top portion of the second housing 724.

The second device 704 further includes structures 733. The structures733 are spatially positioned adjacent to second housing 724 and betweenthe channels formed by the second signal guiding structures 722 and 723.Similar to the structures 731, in some implementations, the structures733 are formed at least partially within second housing 724. Even thoughFIG. 7C shows the structures 733 extending through the entire thicknessof the second housing 724, the structures can extend vertically onlypartially through a portion of the thickness of the second housing 724(e.g., half the thickness of the second housing 724, a quarter of thethickness of the second housing 724).

For convenience, each IC package is referred to as a transceiver ICpackage. Each transceiver IC package can also be called a connector. Inparticular implementations, the transceiver IC package may instead be atransmitter IC package, a receiver IC package, or may be an IC packageconfigured to operate selectively as a transmitter or receiver. Thus,the transceivers can correspond to the paired transmitter IC packagesand receiver IC packages of either FIG. 5A or 6.

Structures 731, 733 are configured to disrupt an electromagnetic fieldassociated with signals propagating across channels of the communicationmodules 701, 703, illustrated by dashed path 734 showing propagationthrough one or more device housing and dashed path 736 showingpropagation of signals through the PCB 710.

FIG. 7D shows a model 758, which is similar to the model 540 shown inFIG. 5B, except for a series of corrugations or structures 762 thatpopulates a portion l_(c) of the housing 760. In the embodiment shown inFIG. 7D, l_(c) is 75% of the length of the housing 750, which can alsothe distance between the transmitter and receiver IC packages 542 and544. The total number of corrugations or structures 762 within l_(c) isN_(g). In the embodiment shown in FIG. 7D, there are 16 corrugations orstructures (i.e., N_(g)=16). The height of the structure 762 is half ofthe thickness t_(c) of the housing 760, and a length of the structure762 is w_(c). The volume of a repeating unit 754 isl_(c)/N_(g)×t_(c)/2×w_(c). l_(p) is the length of the transmitter orreceiver IC package, which has a pyramid shape in the model 768 shown inFIG. 7D. l_(p) is maintained as a constant in the model and is used forcalibration purposes.

FIG. 7E shows a plot 766 of the reflection coefficient S11 between thefrequency of 50 GHz to 70 GHz for one embodiment of the model 768 shownin FIG. 7D. Compared to the plot 560 in FIG. 5C for an unperturbedhousing having no second material, the presence of the 16 corrugationsor structures 762 shifts the minimum of the reflection coefficient S11(˜−8 dB) from 60 GHz in FIG. 5C to about 61 GHz. The maximum of thetransmission coefficient S21 drops from −12 dB in FIG. 5C to about −14dB in FIG. 7E, due to the presence of the 16 structures 762.

FIG. 8 shows a side view diagram 800 illustrating a pair ofcommunication modules including a signal blocking structure andstructures for reducing or blocking parasitic signal transmissionbetween or within the communication modules.

Diagram 800 includes a portion of a first device 802 and a second device804. The first device 802 includes a first communication module 801. Thefirst communication module 801 includes a first transceiver IC package806 and a second transceiver IC package 808 mounted to a first PCB 810.Each of the first transceiver IC package 806 and the second transceiverIC package 808 is at least partially encircled by a respective firstsignal guiding structure 812, 813 similar to the signal guidingstructures described above.

The first signal guiding structures 812, 813 each form a channelextending from the respective transceiver IC package to a surface of afirst housing 814 of the first device 802. For example, the first device802 can be a first mobile phone and the first housing 814 can correspondto the outer case of the first mobile phone.

The first device 802 further includes a first blocking structure 830 inaddition to the structures 831, which are similar to structures 731shown in FIG. 7C. The first blocking structure 830 is spatiallypositioned adjacent to the first PCB 810 and between the channels formedby the first signal guiding structures 812 and 813.

The second device 804 includes a second communication module 803. Thesecond communication module 803 includes a third transceiver IC package816 and a fourth transceiver IC package 818 mounted to a second PCB 820.Each of the third transceiver IC package 816 and the fourth transceiverIC package 818 is at least partially encircled by a respective secondsignal guiding structure 822, 823.

The second signal guiding structures 822, 823 each provide a channelextending from the respective transceiver IC package to a surface of asecond housing 824 of the second device 802. For example, the seconddevice 802 can be a second mobile phone and the second housing 824 cancorrespond to the outer case of the second mobile phone.

The second device 804 further includes a second blocking structure 832in addition to the structures 833, which is similar to structures 733shown in FIG. 7C. The second blocking structure 832 is spatiallypositioned adjacent to the second PCB 820 and between the channelsformed by the second signal guiding structures 822 and 823.

The blocking structures 830 and 832 can be formed from a material thatabsorbs electromagnetic radiation, particularly radio frequencyelectromagnetic radiation including EHF RF electromagnetic radiation.For example, the blocking structure can be composed of a silica-ferritematerial, e.g., a material formed by mixing small iron pieces withsilicon. In some implementations, an epoxy based ferrite material couldbe used as a blocking structure having a suitable heat tolerance. Otherabsorbing materials can be used to form the blocking structure, forexample, other ferrite materials or carbon based materials.

The dimensions of the blocking structure can depend on the material usedand the dimensions of the communication module, e.g., the spacingbetween channels or the width of the IC packages. Additionally, the sizeof the blocking structure can depend on the wavelength of theelectromagnetic signals. For example, the blocking structures may extendtowards the housing and in some cases may be in contact with the housingor even extend through the housing.

Because the leaking signals are part of an electromagnetic field,propagation can be significantly disrupted even without the blockingstructure being directly in a line of sight path of propagation of thesignal. Thus, if a first blocking structure 830 is positioned adjacentto the first housing 814, the blocking structure is able to disruptpropagation both through the first housing 814 and the first PCB 810.

Use of the blocking structure 830/832 and structures 831 and 833 canreduce cross-talk generated by unintended coupling. For example, in someimplementations, cross talk caused by the unintended coupling can bereduced by up to 10 dB relative to the cross talk without the signalblocking structure. Reducing cross-talk can improve performance ofcommunications between paired transmitter and receiver IC packages. Insome implementations, the reduction in cross-talk can also reduceleakage from the device to outside where they might cause interferencewith other devices. This reduction in outside leakage can be beneficialto satisfying various regulatory requirements for devices.

Additionally, in some implementations, the presences of the structures831 and 833 between communication channels can reduce the need for otherabsorbers such as an absorber that surrounds the signal guidingstructures.

As above, each IC package is referred to as a transceiver IC package forconvenience. In particular implementations, the transceiver IC packagemay instead be a transmitter IC package, a receiver IC package, or maybe an IC package configured to operate selectively as a transmitter orreceiver.

Similar to the signal blocking structures described above with respectto FIG. 7, each of the first and second blocking structures 830, 832 areconfigured to disrupt an electromagnetic field associated with signalspropagating across channels of the communication modules 801, 803,illustrated by dashed path 834 showing propagation through one or moreof the device housings and dashed path 836 showing propagation ofsignals through the PCB 810.

As described above, propagation can be significantly disrupted evenwithout being positioned directly in a line of sight path between thechannels. Thus, although the first blocking structure 830 is positionedadjacent to the first PCB 810, the blocking structures are able todisrupt propagation both through the housing and the first PCB 810 asshown by paths 834 and 836.

FIG. 8 shows an example position for signal blocking structures. Howeverother suitable positions can be used. For example, the signal blockingstructure can be positioned at a point between the PCB and the housing,e.g., the signal blocking structure can be elevated over the PCB surfaceby a support structure mounted on the PCB or extending from the housing.In some other implementations, the signal blocking structure ispartially embedded within a recess formed in the housing or a recessformed in the PCB. In some implementations, the relative position of theblocking structure with respect to the PCB and the housing can affectthe degree of cross-talk reduction from the respective sources. Forexample, positioning the blocking structure closer to the PCB may resultin a greater reduction of electromagnetic signals propagating throughthe PCB than the reduction of electromagnetic signals propagatingthrough the housing. Similarly, positioning the blocking structurecloser to the housing may result in a greater reduction ofelectromagnetic signals propagating through the housing than thereduction of electromagnetic signals propagating through the PCB. Theparticular position of the blocking structure can be selected, forexample, to optimize the reduction overall or to optimize the reductionfrom a particular source path, e.g., through the PCB.

FIG. 9 shows a view 900 of a device housing portion 902 incorporating anumber of structures 904. The device housing portion 902 can be, forexample, a portion of a device case e.g., for a mobile phone, tabletdevice, or laptop. In particular, view 900 can represent an interiorportion of the device case.

The structures 904 can be formed by removing material from the devicehousing portion 902 and re-filling voids defined in the device housingportion 902 with a second material. In this way, the exterior surface ofthe device housing portion 902 can be kept smooth and/or planar, withoutdents or bumps. Alternatively, the device housing portion 902 can bedoped at selected location to the desired structures having a differencedielectric constant from the device housing 902. The doped material canalso be foam. “Doping” is consistent with common usage in semiconductorphysics. In this case, it can include secondary insert molding orequivalent. In addition, the device housing portion 902 can also beproduced using other suitable techniques, for example, by 3D printing inwhich the housing portion 902 can be fabricated to include structures ofa second material arranged at specific locations. Various patterns fordistributing structures 904 within the device housing portion 902 can bedefined through a molding process such as injection molding. Using sucha method, the housing will be formed integrally and at the same time asthe structures. The structures 904 are positioned such that when thehousing portion 902 is positioned over a communication module, thestructures 904 are located between the channels of a pair of transceiverIC packages, represented by dashed boxes 906 and 908.

FIG. 10A shows a side view of a first device 1000 having a first housing1002 that incorporates a number of structures 1004. The first device1000 includes a PCB 1006. Positioned on PCB 1006 are a first transceiverIC package 1008 and a second transceiver IC package 1010. The structures1004 are positioned between the two channels formed by each of the firsttransceiver IC package 1008 and the second transceiver IC package 1010.In addition, an absorber 1012 (e.g., a blocking structure like thosedescribed with respect to FIG. 8) can be positioned on the PCB 1006. Thefirst device 1000 is placed in close proximity to a second device 1050having a second housing 1052 that incorporates a number of structures1054. The second device 1050 includes a PCB 1056. Positioned on PCB 1056are a third transceiver IC package 1058 and a fourth transceiver ICpackage 1060. The structures 1054 are positioned between the twochannels formed by each of the third transceiver IC package 1058 and thefourth transceiver IC package 1060. For example, the first transceiverpackage 1008 and the third transceiver IC package 1058 jointly form thefirst channel and the second transceiver IC package 1010 and the fourthtransceiver IC package 1060 jointly form the second channel. Inaddition, an absorber 1062 can be positioned on the PCB 1056. Forsimplicity, signal guiding structures, for example, structures 512, 513,522, and 523 shown in FIG. 5A are not shown in FIG. 10A. In general, thedevices include the signal guiding structures. The signal guidingstructures can be eliminated if a distance to the absorber structures isshort enough. For example, if the absorber is in direct contact with aninterior surface of the case, guiding structures are not needed. In someimplementations, such a structure may add unnecessary complexity.

FIG. 10B shows a top view of the first device 1000 in close proximity tothe second device 1100. For simplicity, the transceiver IC packages1008, 1010, 1058, and 1060 are not shown in FIG. 10B.

FIG. 10C shows a plot 1064 of a plot of crosstalk, each curverepresenting a different degree of suppression. In particular, thetransmission coefficient S21 measures the amount of power transmitted bya transmitter IC package on one portion of the housing that is sensed bya receiver IC package on the other portion of the housing. The housingdoes not include any arrangement of structures (e.g., periodicstructures) or absorbers. The units are dB relative to the desireddirect signal, S21 for example. They are much lower compared to thoseshown in FIGS. 7E-7K because, unlike the structures shown in FIGS.7E-7K, the “unfiltered” original crosstalk is the fraction of the directsignal (straight across) that is diverted along the direction of thecase. A plot 1066 shows the transmission coefficient S21 for a housingthat includes absorber structures. As can be seen in FIG. 10C, thetransmission coefficient S21 is reduced by the presence of theabsorbers. A plot 1068 shows the transmission coefficient S21 for ahousing that includes a periodic arrangement of structures, similar tostructures 1004 and 1054 shown in FIG. 10A. The transmission coefficientS21 is lower when the periodic arrangement of structures are usedinstead of absorbers. A plot 1070 shows the transmission coefficientwhen both absorbers and periodic structures are used. The transmissioncoefficient is lower almost everywhere over the band in this casecompared to all plots 1064, 1066, and 1068. Frequency dependence ofcrosstalk can be due to interactions that involve both constructive anddestructive interference. The relevant metric here is the averagedcrosstalk, not a single excursion where one curve crosses another. FIG.10D shows a side view of a first device 2500 having a first housing 2502that incorporates a number of structures 2504. The first device 2500includes a PCB 2506. Positioned on PCB 2506 are a first transceiver ICpackage 2508 and a second transceiver IC package 2510. The structures2504 are positioned between the two channels formed by each of the firsttransceiver IC package 2508 and the second transceiver IC package 2510.In addition, an absorber 2512 can be positioned on the PCB 2506. Thefirst device 2500 is placed in close proximity to a second device 2600having a second housing 2602 that incorporates a number of structures2604. The second device 2600 includes a PCB 1606. Positioned on PCB 2606are a third transceiver IC package 2608 and a fourth transceiver ICpackage 2610. The structures 2604 are positioned between the twochannels formed by each of the third transceiver IC package 2608 and thefourth transceiver IC package 2610. For example, the first transceiverpackage 2508 and the third transceiver IC package 2608 jointly form thefirst channel and the second transceiver IC package 2510 and the fourthtransceiver IC package 2610 jointly form the second channel. Inaddition, an absorber 2612 can be positioned on the PCB 2606. Adielectric, such as post 2699, may act as a lens and help boostcoupling. When the post 2699 is placed in the desired transmissiondirection, it can help to direct the signal in the correct direction.

FIG. 10E shows a top view of the first device 2500 in close proximity tothe second device 2600.

The structures defined in the housing of the devices can also becombined with other signal blocking structures to reduce undesirablecross-talk. For example, the periodic structure may work alone or withabsorbers.

FIG. 11A shows a portion 1400 of a housing 1402. Instead of a groove ortrench like structure, structures 1404 each having a circular shape canbe defined in the housing 1402. Even though the circular shape ofstructures 1404 shown in FIG. 11A is different from the trench- orgroove-shaped structures shown in FIG. 7A. The composition of thematerial that forms the structures 1404 can be the same as the secondmaterial 752 described in FIG. 7A and other figures above. In theembodiment shown in FIG. 11A, the circular structures 1401 have acenter-to-center distance 1406 that is constant between adjacentstructures. In other words, the structures 1404 shown in FIG. 11A have aregular periodicity. In other embodiments, circular structures can bespaced at irregular intervals from one another, depending on theobjectives for the relevant applications.

Each transceiver IC package can also be referred to as a connector. Ingeneral, structures can be placed where signal propagation is undesired,such as between connectors or they may surround connectors. FIG. 11Bshows an arrangement 1406 of four transceiver IC packages 1408, 1410,1412, and 1414. Structures 1416, which are made of a material differentfrom the material of the housing 1418 can be arranged between pairs ofconnectors as shown in FIG. 11B. The distances between structures 1416may not be uniform, and the shape of the structures can also differ.

FIG. 11C shows an arrangement 1420 of structures 1424 that are arrangedin concentric circles around a connector 1422. The structures 1424 aremade of a material different from that of the housing 1426. Theconcentric circles are arranged alternatively between materials of thehousing 1426.

FIG. 11D shows structures 1428 that have a T-shape. Other shapes besidescircular, groove/trench, rod and T-shape are possible. A distance 1430between structures 1428 need not be constant. The size of the structures1428 also need not be constant.

FIG. 11E shows an example where structures 1430 and 1432 in the form ofgrooves have different heights. A distance 1434 between each structures1430 and 1432 also need not be uniform and may be adjusted according tospecific needs. Different geometries weight performance parametersdifferently. Any filter and gain may be favored over bandwidth or viceversa. In this case, the rejection gain may be stronger at a narrow bandwith a simpler geometry while bandwidth may be favored over a rejectionband with more complicated geometries.

In general, corrugations or groves can be uniform (totally periodic) asshown in FIG. 7C or non-uniform, as shown in FIG. 7A. They can partiallyor completely penetrate the cover structure, as shown in FIG. 7C andFIG. 7A, respectively. Different groove geometries (number and size)would result in different S11 and S21 values. Better S21 values, such asthose lower than −15 dB, demonstrate the enhancement resulting from thegroove structures.

The use of structures (e.g., periodic structures having identicalrepeating units) can help to eliminate the need for absorbers arounddevices and/or transceiver IC packages. These absorbers can be “pictureframe” absorbers that would otherwise surround the devices and/ortransceiver IC packages for reducing cross-talk signals. Reducing oreliminating the use of picture frame absorbers can reduce the materialvolume and free up real estate and lower costs due to the space thematerials may take up. For example, an absorber that is arranged tosurround the guiding structure may be eliminated when the structures areused. In addition, the material used as to define the structures can beflexibly chosen. For example, the structures can be formed by firstremoving material from the housing and re-filling the gaps or voids witha second material (e.g., foam, plastics, nylon . . . etc.) to provide ahousing having a smooth and/or planar exterior surface. Alternatively,the structures can also be easily implanted within the cases of devices(e.g., plastic cases) for simple integration. Implanting can involveputting the structures in devices. For example, rather than molding thestructures directly into the case, the cases may be made with a slot forseparately made structures to be inserted therein.

In the example implementations described above, a portion of the housingthrough which signals pass to or from an IC package of a communicationcan be formed of a different material than other portions of thehousing. For example, in some implementations a portion of the housingcan be formed from a metallic material that would inhibit passage of thesignals. To allow passage of the signals, a portion of the housing alongthe signal paths can be formed from another material, for example, aninsert of a plastic material that allows signal passage.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyinvention or on the scope of what may be claimed, but rather asdescriptions of features that may be specific to particular embodimentsof particular inventions. Certain features that are described in thisspecification in the context of separate embodiments can also beimplemented in combination in a single embodiment. Conversely, variousfeatures that are described in the context of a single embodiment canalso be implemented in multiple embodiments separately or in anysuitable subcombination. Moreover, although features may be describedabove as acting in certain combinations and even initially be claimed assuch, one or more features from a claimed combination can in some casesbe excised from the combination, and the claimed combination may bedirected to a subcombination or variation of a sub combination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various system modulesand components in the embodiments described above should not beunderstood as requiring such separation in all embodiments, and itshould be understood that the described program components and systemscan generally be integrated together in a single software product orpackaged into multiple software products.

Particular embodiments of the subject matter have been described. Otherembodiments are within the scope of the following claims. For example,the actions recited in the claims can be performed in a different orderand still achieve desirable results. As one example, the processesdepicted in the accompanying figures do not necessarily require theparticular order shown, or sequential order, to achieve desirableresults. In some cases, multitasking and parallel processing may beadvantageous.

What is claimed is:
 1. An apparatus comprising: a communications modulecomprising two or more integrated circuit packages each integratedcircuit package including at least one transmitter, receiver, ortransceiver; and a device housing portion for an electronic device,wherein the housing portion comprises a planar portion substantiallyparallel to a communications module of the device, the planar portion ofthe housing comprising: a first region formed from a first material andconfigured to be in a transmission path of a first electromagneticsignal, associated with a first integrated circuit package, whentransmitted to or from the device; a second region formed from the firstmaterial and configured to be in the transmission path of a secondelectromagnetic signal, associated with a second integrated circuitpackage, when transmitted to or from the device; and a third regioncomprising an arrangement of structures formed from a plurality ofsegments of the first material and a plurality of segments of a secondmaterial, wherein the first material has a first dielectric constantthat allows propagation of electromagnetic signals and the secondmaterial has a second dielectric constant, wherein the arrangement ofthe first material and the second material provides a bandpass filter ofelectromagnetic signals.
 2. The apparatus of claim 1, wherein the secondmaterial is an absorptive material.
 3. The apparatus of claim 1, whereinthe width of the second material is selected based on a wavelength ofthe first electromagnetic signal.
 4. The apparatus of claim 1, whereinthe width of the first material is selected based on a wavelength of thefirst electromagnetic signal.
 5. The apparatus of claim 1, wherein thewidth of the second material varies through the arrangement ofstructures to provide a wider frequency range of filtering.
 6. Theapparatus of claim 1, wherein the magnitude of the electromagneticsignal filtering depends on the number of segments of the secondmaterial in the arrangement of structures.
 7. The apparatus of claim 1,wherein a thickness of the second dielectric material is less than athickness of the planar portion of the housing.
 8. The apparatus ofclaim 1, wherein the arrangement of structures comprises a plurality ofconcentric circles of the first material and the second material,respectively, positioned relative to the first region.
 9. The apparatusof claim 1, wherein forming the arrangement of structures comprisesremoving portions of the planar portion of the housing and filling theremoved portions with the second material.
 10. An apparatus, comprising:a device housing portion for an electronic device, wherein the housingportion comprises a planar portion substantially parallel to acommunications module of the device, the planar portion of the housingcomprising: a first region formed from a first material and configuredto be in a transmission path of electromagnetic signals, associated witha corresponding integrated circuit packages, when transmitted to or fromthe device; a second region comprising an arrangement of structuresformed from a plurality of segments of the first material and aplurality of segments of a second material, wherein the first materialhas a first dielectric constant that allows propagation ofelectromagnetic signals and the second material has a second dielectricconstant, wherein the arrangement of the first material and the secondmaterial provides a bandpass filter of electromagnetic signals.
 11. Theapparatus of claim 10, wherein the second material is an absorptivematerial.
 12. The apparatus of claim 10, wherein the width of the secondmaterial is selected based on a wavelength of the electromagneticsignals.
 13. The apparatus of claim 10, wherein the width of the firstmaterial is selected based on a wavelength of the electromagneticsignals.
 14. The apparatus of claim 10, wherein the width of the secondmaterial varies through the arrangement of structures to provide a widerfrequency range of filtering.
 15. The apparatus of claim 10, wherein themagnitude of the electromagnetic signal filtering depends on a number ofsegments of the second material in the arrangement of structures. 16.The apparatus of claim 10, wherein a thickness of the second dielectricmaterial is less than a thickness of the planar portion of the devicehousing portion.
 17. The apparatus of claim 10, wherein the arrangementof structures comprises a plurality of concentric circles of the firstmaterial and the second material, respectively, positioned relative tothe first region.
 18. The apparatus of claim 10, wherein forming thearrangement of structures comprises removing portions of the planarportion of the housing and filling the removed portions with the secondmaterial.